1. Field of the Invention
This invention relates to a wheel unit for a slidable infant chair which enables an infant seated in the chair to walk around freely.
2. Description of the Prior Art
A slidable infant chair is supported by an annular frame which is provided with a plurality of wheels, enabling the infant chair to be slidable. Referring to FIG. 1, a common wheel unit includes a wheel cover 1, a wheel 12, a flat head rod 2, a rod cap 3, and a fixing sleeve 41. A horizontal rivet 11 is inserted through the wheel 12 and then riveted to the center of the wheel cover 1 so as to assemble them. The flat head rod 2 penetrates through the left portion of the wheel cover 1 and the rod cap 3, and then is riveted at both ends so as to assemble them fixedly. The rod cap 3 is covered with flanges 31 on its outer surface, and is fixedly inserted in the fixing sleeve 41 under the annular frame 4.
FIG. 2 shows another prior wheel unit, which includes a spherical wheel 1, a rod 2, and a rod cap 31 under an annular frame 3. The spherical wheel 1 has an upward rod supporter 11 with a hollow 111 inside, and close the bottom of the hollow 111 has a flanged ring 112. The said rod cap 31 has a downward opening 311, and there is a flanged ring 312 close the top of the opening 311. The said rod 2 has two snap ends, close which have ringed grooves 21 and 22 respectively, so as to be tightly inserted into the hollow 111 and the opening 311. In this way, the wheel unit is assembled and attached to the annular frame 3.
According to the description above, the two prior wheel units bear following disadvantages in their structures.
1. In the process of assemblage, mechanical tools are needed. Consequently, the process is so complicated that a consumer can not assemble the wheel units by himself.
2. The wheel units can not be disassembled once they are assembled. Therefore, they occupy much space and cost much while being packed and transported.
3. If one of the wheels under an annular frame should break down or come loose, the whole annular frame with the rest wheels has to be replaced. Thus, the structures of the prior wheel units cause much inconvenience. It is not economical for a consumer to repair them.